1. Field of Invention
The present invention relates to the field of graphics rendering and display. In particular, the present invention describes an efficient method and apparatus for determining texture coordinates for lines and polygons.
2. Description of Related Art
Computer systems display graphical images through a process of rendering a computer model. The graphical images are typically made from tens of thousands of pixels (picture elements). The computer model can be represented within the computer system as a number of polygons and a texture map. A texture map represents a texture that is to be wrapped around a 3-D model. Computer systems render the computer model by generating pixels from the polygons and the texture map.
For example, assume a programmer wishes to display a can of soda pop in a computer system. The programmer can enter a 3-D model of a cylinder and a texture of a soda pop label. The computer system can then display an image of a soda pop can by mapping the texture onto the 3-D model through the rendering process.
Rendering images requires large amounts of computer power. A typical image can include thousands of polygons and hundreds of texture maps. To determine each pixel value, the speed of the mapping of the texture to the polygons can greatly affect the speed of the rendering of the image. It is desirable to increase the speed of the rendering process because larger, more detailed, images can be displayed.
One improvement to the speed of the rendering process has been to develop specialized hardware. The hardware can render numerous pixels at a time. However, this specialized hardware is expensive and does not help the large installed base of computer systems that do not have this specialized hardware.
Therefore it is desirable to improve the efficiency of the rendering process, and specifically the mapping process, by developing a more efficient method and apparatus for performing the mapping process.